Stumped.... best guess, some sort of conularid, or conularid+stromatoporiod mutualism; Silurian Clinton Group, Blair County PA USA

[SteveE]

From USA, Pennsylvania, Blair County...... Silurian Clinton Group.

 

In profile, this looks conical, with the point down in the sediment rather like a conularid.   But viewed from above, it is ROUND. 

 

 

 

 

 

 

Edited December 11, 2022 by SteveE

[Darktooth]

If I remember correctly I got sponges from a member here that looked like these. Atleast from the top view.

[SteveE]

1 minute ago, Darktooth said:

If I remember correctly I got sponges from a member here that looked like these. Atleast from the top view.

I have a few stromatoporoids that fit that description, but from an early Devonian formation (Keyser limestone).   The depth of these things in 3d is what really throws a wrench in that ID.

 

[Darktooth]

2 minutes ago, SteveE said:

I have a few stromatoporoids that fit that description, but from an early Devonian formation (Keyser limestone).   The depth of these things in 3d is what really throws a wrench in that ID.

 

Maybe that is what they were labeled as. I think the specimens I am talking about were an auction win from member @Scylla. I will have to see if i can find them. Definitely look the same as yours.

[SteveE]

14 minutes ago, Darktooth said:

Maybe that is what they were labeled as....

Probably.  Fossil sponges, so far as I know, all had exoskeletons of (its debated) calcium carbonate and/or aragonite, and were all part of "Stromatoporoidea", which is now extinct.. 

[SteveE]

Anybody have any similar-looking ironstone from the Clinton Group?

[Scylla]

On 12/11/2022 at 7:00 PM, SteveE said:

Probably.  Fossil sponges, so far as I know, all had exoskeletons of (its debated) calcium carbonate and/or aragonite, and were all part of "Stromatoporoidea", which is now extinct.. 

Not the glass sponges. I have no idea what these are.

[DPS Ammonite]

On 12/11/2022 at 5:00 PM, SteveE said:

Probably.  Fossil sponges, so far as I know, all had exoskeletons of (its debated) calcium carbonate and/or aragonite, and were all part of "Stromatoporoidea", which is now extinct.. 

 

I assume that this comment was directed toward stromatoporoids specifically and not sponges in general. Stromatoporoids were made of calcium carbonate. 

Edited December 15, 2022 by DPS Ammonite

[SteveE]

On 12/13/2022 at 8:52 AM, Scylla said:

Not the glass sponges.

Thanks, I was previously unware of that group